1. Field of the Invention
This invention relates to a power transmitting' device for use in an oil well pump and, more specifically, to such a device which provides speed reduction from a single input shaft which is driven by a rotating power source to two output shafts which are capable of driving a crank means to provide the power to a reciprocating pumping device of the oil well pump and to a method for making the same.
2. Description of the Prior Art
It is common in the oil industry to utilize reciprocating oil well pumps of the type which are powered by a rotating power source. Typically, the power source is an electric motor although diesel driven engines or the like could also be utilized. Because electric motors and engines operate more efficiently at higher speeds and the reciprocating motion of the pump is at a significantly lower speed, some speed reduction is required in the transmission of power from the power source to the reciprocating pump. Although some reduction in speed can be produced at the output of the motor through a belt and pulley or chain drive means, it has been found preferable to include a power transmitting device which includes significant speed reduction between the power source and the pump.
U.S. Pat. Nos. 1,972,660; 1,979,803; 3,183,728; 3,427,887; 3,621,723; 3,706,234; 3,867,846 and 4,051,736 disclose oil well pumps of the type mentioned above and, because of the forces required to operate the pumps, teach that it is advantageous to utilize a dual pitman or connecting rod configuration for balanced loading on the power transmitting device and other pump components. Each includes dual output shaft means from a power transmitting, speed reducing device which drive some type of crank arms for the operation of the pitmen. It is common to include counterweights on the crank arms for even loading during operation of the pump. However, the walking beam configurations to which the pitmen are connected are of various designs as are the means employed for coupling the power source to the input of the speed reducer.
Although the speed reducers utilized in the oil well pumps disclosed in the patents mentioned hereinabove might differ, they each appear to utilize a single input shaft which drives a series of spur, helical or herringbone gears to transmit the power to the output shaft. The output shaft is parallel to the input shaft and has crank means mounted at each end thereof. While these types of power transmitting, speed reducers appear to be most common in recent oil well pump installations, there has heretofore been utilized other gear means for transmitting power from and reducing the speed of the power source. U.S. Pat. Nos. 1,821,216; 1,858,185; 1,915,827; 2,161,298; 2,197,730; 3,208,291 and 3,221,569 include speed reducers having input shafts which are not parallel to the output shafts. A number of these speed reducers can be seen to include worm gear drives although the detailed operation of others is not fully disclosed. In any case, they each disclose that the output shaft is directly coupled to a single or dual crank means for the operation of the reciprocating pump.
While any number of these devices might have been and continue to be successfully utilized in the oil pumping field, there remains a need to provide a power transmitting speed, reducing device which is reliable and inexpensive to provide. Obviously, any power transmitting speed, reducing device, which might be more efficient than the spur, helical, herringbone or worm gear devices used heretofore, would be desirable to reduce the design requirements and operating costs for the power source. Additionally, any such installation should include means for effectively maintaining or repairing the power transmitting, speed reducer device as quickly and conveniently as possible so there would be less interference with the operation of the oil well pump.